This study was performed to evaluate the ecophysiological acclimation of Catalpa bungei plantlets to different light conditions. We hypothesized that the acclimation of old and newly developed leaves to both increasing and decreasing irradiance should follow different patterns. The growth, photosynthesis, chlorophyll (Chl) content, and Chl fluorescence response were examined over a range of light treatments. The plants were grown under fixed light intensities of 80% (HH), 50% (MM), 30% (LL) of sun light and transferring irradiance of 80% to 50% (HM), 80% to 30% (HL), 30% to 50% (LM) and 30% to 80% (LH). For old leaves, light-saturation point, photosynthetic capacity, dark respiration rate of LH were lower than that of HH, while HL were higher than LL, indicating that light-response parameters were affected by the original growth light environment. Initial fluorescence increased and variable fluorescence decreased in LH and LM after transfer, and the PSII damage was more serious in LH than that in LM, and could not recover within 30 d. It suggested that the photoinhibition damage and recovery time in old leaves was related to the intensity of light after transfer. For the newly emerged leaves with leaf primordia formed under the same light environment, a significant difference was observed in leaf morphology and pigment contents, suggesting that previous light environment exhibited carry-over effect on the acclimation capacity to a new light environment. Our result showed that thinning and pruning intensity should be considered in plantation management, because great changes in light intensity may cause photoinhibition in shade-adapted leaves., J. W. Wu, Y. Su, J. H. Wang, Q. He, Q. Qiu, J. W. Ma, J. Y. Li., and Obsahuje bibliografii
Gastrointestinal form is the second stage of the Acute Radiation Syndrome (ARS) with a threshold dose of 8 Gy. It represents an absolutely lethal clinical-pathological unit, enteritis necro-hemorrhagica (duodenitis, jejunitis, ileitis, respectively) with unknown causal therapy. The purpose of our study has been to evaluate the morphological changes in a model of radiation-induced enteritis in rats and estimate the significance of changes in biodosimetry. Wistar rats were randomly divided into 21 groups, 10 animals per group. Samples of the jejunum were taken 24, 48, 72, and 96 h after the whole-body γ-irradiation with the doses of 1, 5, 10, 15, and 20 Gy, and routinely stained with hematoxylin and eosin. Five morphometric markers – intercryptal distance, enterocytal height on the top and base of villus, length of basal lamina of 10 enterocytes and enterocytal width – in irradiated rat jejunum were examined. The results were compared with sham-irradiat ed control group. After lethal doses of irradiation, all morphometric parameters of jejunum significantly changed. With the exception of intercryptal distance, they might be considered as suitable biodosimetric markers under these experimental conditions. Our morphometry results in radiation-induced jejunitis are in accordance with those in other studies. We were the first who quantified morphological post-irradiation changes in animal jejunum. Some of them might be used under experimental conditions. This experimental study is a predecessor of the clinical assessment of a specific marker. Under clinical practice, the sensitive biodosimetric parameter could serve as one of the guidance for evaluation of the absorbed dose in irradiated troops as well as rescue workers. This is in accordance with tasks and Standardization Agreement of the North Atlantic Treaty Organization., D. Driák, J. Österreicher, J. Vávrová, Z. Řeháková, Z. Vilasová., and Obsahuje bibliografii a bibliografické odkazy
The recognition of aquatic organisms plays a crucial role in the monitoring of the pollution and for the adoption of rapid preventive actions. A compact microscopic optical imaging system is proposed in order to acquire and treat the multibands fluorescence of several pigments in phytoplankton organisms. Two algorithms for automatic recognition of phytoplankton were proposed with a minimum number of calibration parameters. The first algorithm provides a morphological recognition based on "watershed" segmentation and Fourier descriptors, while the second one builds fluorescence pigment images by "k-means" partition of intensity ratios. The operation of these algorithms was illustrated by the study of two different organisms: a cyanobacteria (Dolichospermum sp.) and an alga (Cladophora sp.). The family and the genus of these organisms were then classified into a database which is independent of the size, the orientation and the position of the specimens in the images., M. Lauffer, F. Genty, S. Margueron, J. L. Collette., and Obsahuje bibliografii
The riparian forests along the Tarim River, habitats for Populus euphratica establishment, are subjected to frequent flooding. To elucidate adaptive strategies that enable this species to occupy the riparian ecosystem subjected to seasonal or permanent water-logging, we examined functional characteristics of plant growth, xylem water relations, leaf gas exchange, chlorophyll (Chl) content and fluorescence, soluble sugar and malondialdehyde (MDA) content in P. euphratica seedlings flooded for 50 d. Although flooded seedlings kept absorbing carbon throughout the experiment, their shoot and root growth rates were lower than in non-flooded seedlings. The reduced leaf gas exchange and quantum efficiency of PSII of flooded seedlings resulted possibly from the reduction in total Chl content. Content of soluble sugar and malondialdehyde in leaves were higher in flooded than in control seedlings. Soil flooding induced hypertrophy of lenticels and increased a stem diameter. These responses were responsible for species survival as well as its success in this seasonally flooded riparian zone. Our results indicate that P. euphratica is relatively flood-tolerant due to a combination of morphological, physiological, and biochemical adjustments, which may support its dominance in the Tarim riparian forest., B. Yu, C. Y. Zhao, J. Li, J. Y. Li, G. Peng., and Obsahuje bibliografii
This paper describes the technical information and performance of a new multi-objective chamber system enabling the control of environmental variables (e.g., temperature, CO2, air humidity, wind speed, and UV-B radiation) for understanding plant responses to climate change. Over a whole growing season, four different climate scenarios were evenly programmed into the system’s 16 chambers as ambient environment (AMB), elevated temperature (ET), elevated CO2 concentration (EC) and elevated temperature and CO2 concentration (ETC). Simultaneously, the chamber effects were assessed regarding the physiological responses and growth of a boreal perennial grass (reed canary grass, Phalaris arundinacea L.). During the growing season, the chamber system provided a wide variety of climatic conditions for air temperature (T a), relative humidity (RH) and CO2 concentration (C a) in the AMB chambers following outside conditions. The target temperature (+3.5°C) was achieved to a good degree in the ET and ETC chambers, being on average 3.3°C and 3.7°C higher than ambient conditions, respectively. The target concentration of CO2 (700 ppm) was also well achieved in the EC and ETC chambers, being on average 704 ppm and 703 ppm, respectively. The stable airflow condition inside all of the chambers provided a homogeneous distribution of gases and temperature. The decreases in RH and increases in vapour pressure deficit (VPD) in the elevated temperature chambers were also maintained at a low level. Chamber effects were observed, with some physiological and growth parameters of plants being significantly lower in the AMB chambers, compared to outside conditions. The plant growth was negatively affected by the reduced radiation inside the chambers., X. Zhou ... [et al.]., and Obsahuje bibliografii
The long QT syndrome (LQTS) is a monogenic disorder characterized by prolongation of the QT interval on electrocardiogram and syncope or sudden death caused by polymorphic ventricular tachycardia (torsades de pointes). In general, mutations in cardiac ion channel genes (KCNQ1, KCNH2, SCN5A, KCNE1, KCNE2) have been identified as a cause for LQTS. About 50-60 % of LQTS patients have an identifiable LQTS causing mutation in one of mentioned genes. In a group of 12 LQTS patients with no identified mutations in these genes we have tested a hypothesis that other candidate genes could be involved in LQTS pathophysiology. SCN1B and KCND3 genes encode ion channel proteins, ANK2 gene encodes cytoskeletal protein interacting with ion channels. To screen coding regions of genes SCN1B, KCND3, and 10 exons of ANK2 following methods were used: PCR, SSCP, and DNA sequencing. Five polymorphisms were found in screened candid ate genes, 2 polymorphisms in KCND3 and 3 in SCN1B. None of found polymorphisms has coding effect nor is located close to splice sites or has any similarity to known splicing enhancer motifs. Polymorphism G246T in SCN1B is a novel one. No mutation directly causing LQTS was found. Molecular mechanism of LQTS genesis in these patients remains unclear., M. Raudenská, A. Bittnerová, T. Novotný, A. Floriánová, K. Chroust, R. Gaillyová, B. Semrád, J. Kadlecová, M. Šišáková, O. Toman, J. Špinar., and Obsahuje bibliografii a bibliografické odkazy
Dokumentační fotografie vegetace a krajiny má specifické požadavky na prosvětlené snímky zachycující detailní kresbu tvarů listů a přesné barvy květů. V digitální fotografii dlouhou dobu chyběly kvalitní fotoaparáty kompaktních rozměrů, které byly navíc velmi drahé. Naštěstí rychlý vývoj technologií přinesl takové možnosti snímání, které jsou prakticky už na úrovni tradičních fotopřístrojů středního formátu., Vegetation and landscape documentation photography have special requirements for clear pictures with details of leaf shapes and flower colors. Hence for a long time in digital photography there was a lack of high quality compact cameras, which in any case were very expensive. Fortunately, rapid technological developments have provided options comparable with the middle-format cameras of the past., and Tomáš Kučera.